Graduate medical education

In most industrialized countries, graduating from medical school, with a M.D. or M.B. degree, does not qualify one for independent practice without postgraduate medical education. The exact terminology for this training, which consisted of clinical experience under supervision, with steadily increasing responsibility, varied with the country, and, even within a country, with the institution.

In the U.S., the first year of supervised practice was called an internship, the next several years of specialty training a residency, and additional subspecialty training was called a fellowship. The term externship is sometimes used to describe a period of clinical experience before one graduates from medical school.

With greater trends toward specialization, often beginning immediately after graduation, a trend is to refer to postgraduate year (PGY). The first year after graduation is PGY-1, the next year PGY-2, and so forth.

Internship

Clasical internships were "rotating": time was spent in internal medicine and surgery, and, depending on the program, other specialties such as pediatrics or pathology. More recently, if the graduate is clear about future plans, it has been possible to take "straight" internships, such as a full year in internal medicine or surgery.

Again depending on the jurisdiction, it might be possible to get an independent medical license after PGY-1. Realistically, one who did so would have little flexibility, and might not be able to get hospital admitting privileges. Modern postgraduate medical education should be regarded as a minimum of four years.

Residency

The length of residencies for primary specialties vary with the organization — usually called a board — supervising the specialty. The minimum is three years. Even within residency, internal medicine, surgery, pediatrics, and emergency medicine are often considered "general clinical"; a specialty, such as radiology, may insist on a year or two of general clinical experience before entering the specific residency. In the other direction, some boards let a graduate start with what might be considered a subspecialty, such as orthopedics starting in PGY-1.

Primary specialty residencies range from three to five years. Again, it will depend on the specialty board as to whether someone could spend PGY-1 on a service, then PGY-2 and PGY-3 in that same service, and then apply for the basic certification in the specialty.

Fellowship

After completion of a residency, there may be examinations to pass, but it is almost always adequate to go into independent practice in a primary specialty. Fellowship training, however, can follow, and to multiple levels of sub-specialization.

For example, cardiology and infectious disease, among others, are subspecialties of internal medicine. Cardiology is a three-year program, which makes one board-eligible in that subspecialty. A graduate, however, may choose to go further; the terms tertiary and quaternary are becoming more common than sub-sub-specialty and the like. A cardiology fellow might choose not to go into general cardiology after PGY-6 or PGY-7, the number of years depending on whether PGY-1 counted against the primary specialty.

Let us assume the graduate took a straight PGY-1 medicine year, so PGY-6 is complete. PGY-7 could be a fellowship in invasive cardiology, which qualifies one to perform intravascular diagnostic procedures such as cardiac catheterization, angiography, and elecrophysiological mapping. Yet another year would be required to qualify in interventional cardiology involving the performing of disease-modifying interventions such as angioplasty, atherectomy, stenting, or electrophysiology ablation or pacemaker installation.

Interdisciplinary broadening

Some graduates decide to combine, perhaps, two primary specialties and a related subspecialty. One might start in pediatrics, complete a residency, and then take two years of general radiology, followed by a year of pediatric radiology. A fair number of secondary, tertiary and quaternary programs allow entry from a variety of specialties. Pain management most often is considered a specialty of anesthesiology, but graduates may well enter a pain management fellowship from pediatrics, psychiatry, or neurology.

Research orientation

Another option is to take some level of specialty training, interspersing one or more years of clinical work with pure research, adding a Ph.D. degree to the M.D. degree. Some programs allow the MD-PhD process to begin in medical school, perhaps taking a year or two of basic medical science between medical school years 2 and 3, and, somewhere in the postgraduate training, taking a year or more to do a dissertation. The result of the latter would be having board eligibility and a PhD.

Other combined options

There are more applied supplemental programs, the most common being the Master of Public Health (MPH) degree, which usually adds a year or two to a residency in other than public health proper. A number of terminal masters' programs are emerging in areas such as outcomes research and medical quality. Graduates interested in medical administration may combine their postgraduate medical education with a master's in business education or, specifically, medical administration.